Will D.C. lose yet another public space — Union Square?

“IN THE NAME of security.” It’s a phrase to which residents of the District have become wearily accustomed, as streets have been closed to traffic, ugly barriers and bollards erected and historic views blocked. Now comes word of the surreptitious decision to strip part of the Mall from National Park Service jurisdiction for security reasons. It’s only natural to worry that the public will be further restricted in what can be seen and done in the capital.

Union Square, an 11-acre plot that contains the Grant Memorial and the Capitol Reflecting Pool, lies just west of the Capitol and is one of the Mall’s most popular and photographed spots. Since the 1930s, the Park Service has managed it. But as The Post’s Michael E. Ruane has reported, a provision tucked into the recent omnibus spending bill transfers the land — at the behest of House and Senate security officials — to the Architect of the Capitol. Neither the Park Service, which has been developing plans to refurbish the area as First Amendment demonstration space, nor the Architect of the Capitol was consulted or apprised of the measure. Slipped into the giant appropriations bill, it was approved without discussion or debate.

Terrance W. Gainer, the Senate’s sergeant at arms, defended the transfer as necessary to bring the parcel under the umbrella of Capitol security. He said he and his House counterpart had long been worried about security shortfalls and pushed leadership to make the change. He minimized the impact to the public as “a transfer without huge distinction” and told us of his confidence that plans would be developed to enhance security in an attractive way without impeding the public. “There will be no new closures, 3rd street will not be affected. The current open space remains the same,” he wrote us in an e-mail.

Clearly, though, the concept being developed by park officials to take advantage of the site’s hardscape for protests — thus providing some relief to the Mall’s downtrodden grassy areas — was unsettling to security officials and ultimately congressional leaders who unwisely signed off on the plan. Because of Washington’s fortress mentality, numerous streets around the Capitol have been closed, the landscape has been littered with unsightly barriers and visitor flow has been restricted. Now it seems that national protests and other events will be moved farther from one of the great symbols of America’s open society. That’s wrong, and unnecessary.